Cardiac assist devices are increasingly being used for long term support. As patient survival times increase substantially, device wear-out will increasingly play a role in the clinical management of patients with long term devices. Most of the extended use devices utilize flexing polymer membranes. Whereas, long term polymer abrasion may be a primary failure mode for these devices, the detection of polymer wear would be valuable information in the clinical management of patients. The ultimate objective of the research proposed here is to develop a smart polymer, which has embedded wear indicators. As the polymer is gradually abraded, a sensor onboard the device will detect different levels of wear, and a status of the device wear-out will be transmitted to the clinical management team. Detailed studies in Phase I will evaluate a smart polymer designed to indicate both a moderate and severe level of wear. The need for wear-out indicators, such as that developed here, will become increasing important as the number of patients with long term cardiac assist devices increases, and detailed device monitoring and management becomes logistically more difficult. Consequently, the incorporation of device wear-out, and other mission critical sensors should become prevalent in future generations of all long term cardiac assist devices.